I recd my new PSU - thanks! But, I notice it only has one output plug whereas the Apollo has two plug receptacles. My off-the-shelf PSU had a cable with an extra head on the end and that worked fine. How should I plug in the new PSU to the Apollo unit?
Just plug it into the right port. Remember to never plug another PSU/PSU cable into the spare port, this will either blow up one of the PSUs or cause a fire.
What? your only supposed to plug in ONE PSU cable?

the quick start guide says to "Plug in both 6 Pin PCIE power cables from your ATX or server power supply"
never mind I think I miss read that...